<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <h1>{{msg}}</h1>
        <h1 v-once>{{msg}}</h1>
    </div>
    <script src="../js/vue.js"></script>
    <script>
        const app = Vue.createApp({
            data() {
                return {
                    msg: "test"
                }
            }
        }).mount("#app");
    </script>
</body>
</html>